U of S | Mailing List Archive | alt-photo-process-l | RE: Question re dpi for scan...

RE: Question re dpi for scan...




I admit that my knowledge in this area is untested and sketchy but I determine scan resolution by what size and on which type of printer I will end up printing a transparency. Right now I am using an Epson 2200 and making negatives on 13 x 19 substrate (the Arista transparency film). I still don't understand the specifics (whether it has to do with number of inks, droplet size, whatever) but I always out put the negatives on the 2200 at 360 dpi. So I scan at a ppi to achieve an image size that I won't have to upscale in PS. So when I scan my pollen samples and leaves they may be very small but the resolution will allow me to make a 12 x 12 at 360 dpi.

There are different approaches or workflows practiced for scanning film. Without making an explanation complicated the description you list above sounds reasonable and if you are happy with it don’t fix it.

However you don’t mention what scanner you are using or how many ppi you are scanning at. Both will have a great influence on the quality of the printed digital negative or inkjet print. Perhaps a visit to Wayne Fulton’s scan tips page will help with that part of the workflow. The page is a bit dated but the concepts are still accurate today. Visit:

http://www.scantips.com/ for details.

> What are other outputing negatives at on say a 4800 or 4880 and why?

As I read and interpret your post you maybe confusing image printing resolution with the resolution of the image file at final size. Whether you are using a 2200 or one of the larger Epson printers most people will select 1440 or 2880 dpi (both multiples of 360 dpi) for their image printing resolution. The truth is not a lot of difference is likely to be seen between one or the other (1440 or 2880 dpi). It will affect the amount of ink deposited on the transparency substrate which in the end will have an impact on the final densities and density range of the negative being produced. Which ever you choose, use those same values through out your testing and final printing of negatives.

FWIW, with my Epson 2200 I use 2880 for inkjet prints and negatives and when I use my 3800 I use 1440 for inkjet prints and 2880 for inkjet negatives.      

I hope this helps,